Washed processing is one of the most common coffee processing methods, the intention is to highlight the bean itself rather than influencing it with the outer layers of the cherry.
Ultimately a washed coffee gives a cleaner cup, this means the body of the coffee displays more clarity of the true flavours. The body is also lighter (think intensity).
The process starts with the beans being passed through a depulping machine. This machine takes the whole cherry, splits it open, and extracts the beans (every cherry has two beans inside). The cherry flesh is discarded, often repurposed on the farm.
Extracted beans are then sent to a washing station. This can be in the form of a machine, a fermentation method, or manually by hand.
Washing the beans removes the mucilage layer, which contains high amounts of sugars and alcohols. If left on the bean, the mucilage will impart those compounds into the bean which obscures the flavour.
We consider washed coffee as a balance between the science of farming and the art of production. An outstanding washed shows the coffee was grown in the perfect conditions and the farmer crafted the attributes out of those conditions.